This invention is generally related to intraluminal procedures such as coronary angioplasty procedures.
Percutaneous transluminal coronary angioplasty (PTCA) is a widely used procedure for the treatment of coronary heart disease. In this procedure, a balloon dilatation catheter is advanced into the patient's coronary artery and the balloon on the catheter is inflated within the stenotic region of the patient's artery to open up the arterial passageway and thereby increase the blood flow therethrough. To facilitate the advancement of the dilatation catheter into the patient's coronary artery, a guiding catheter having a preshaped distal tip is first percutaneously introduced into the cardiovascular system of a patient by the Seldinger technique through the brachial or femoral arteries. The catheter is advanced therein until the preshaped distal tip of the guiding catheter is disposed within the aorta adjacent the ostium of the desired coronary artery. The guiding catheter is twisted or torqued from the proximal end, which extends out of the patient, to guide the distal tip of the guiding catheter into the ostium. A balloon dilatation catheter may then be advanced through the guiding catheter into the patient's coronary artery until the balloon on the catheter is disposed within the stenotic region of the patient's artery. The balloon is inflated to open up the arterial passageway and increase the flow of blood.
One type of dilatation catheter frequently used in PTCA procedures is an over-the-wire type balloon dilatation catheter which has an inner lumen extending therein adapted to slidably receive a guidewire. When using an over-the-wire dilatation catheter, a guidewire is usually inserted into the inner lumen of the dilatation catheter before it is introduced into the patient's vascular system and then both the catheter and the guidewire are advanced through the guiding catheter to its distal tip which is seated within the ostium of the desired coronary artery. The guidewire is first advanced out the seated distal tip of the guiding catheter into the desired coronary artery until the distal end of the guidewire extends beyond the lesion to be dilatated. The dilatation catheter is then advanced out of the distal tip of the guiding catheter into the patient's coronary artery, over the previously advanced guidewire, until the balloon on the distal extremity of the dilatation catheter is properly positioned across the lesion to be dilatated. Once properly positioned across the stenosis, the dilatation balloon is inflated one or more times to a predetermined size with radiopaque liquid at relatively high pressures (e.g., generally 4-12 atmospheres) to dilate the stenosed region of a diseased artery. After the balloon inflations, it is finally deflated so that the dilatation catheter can be removed from the dilated stenosis and blood flow will resume. Commercial over-the-wire type dilatation catheters including the SIMPSON ULTRA LOW PROFILE.RTM., the HARTZLER ACX.RTM., the HARTZLER ACX II.RTM., the PINKERTON .018.TM. and the ACS TEN.TM. balloon dilatation catheters are available from the assignee of the present invention, Advanced Cardiovascular Systems, Inc. (ACS).
Fixed-wire type dilatation catheter systems are also utilized very frequently in PTCA procedures. This type of dilatation catheter has a guidewire or guiding member secured within it. A fixed-wire dilatation catheter provides a low profile, i.e. small transverse dimensions, because it does not have an inner tubular member which is characteristic of commercially available over-the-wire dilatation catheters. Commercial fixed-wire dilatation catheters including the HARTZLER EXCEL.RTM., the HARTZLER LPS.RTM. and the SLALOM.TM. dilatation catheters are available from ACS.
During an angioplasty procedure with an over-the-wire dilatation catheter, if there is a need to replace the dilatation catheter usually a guidewire extension wire such as disclosed in U.S. Pat. No. 4,827,941 is secured to the proximal end of the guidewire and the in-place dilatation catheter is withdrawn from the patient and removed from the guidewire and the extension wire. A replacement dilatation catheter is mounted onto the extension wire and advanced over the extension wire and the in-place guidewire to the desired location which is usually the prior location of the in-place catheter removed from the patient so that there is no loss of access to the desired location within the body lumen. While this catheter exchange procedure is widely practiced, it is not very convenient.
If a fixed-wire dilatation catheter within a patient needs to be exchanged for another catheter, e.g. because a different size balloon is needed, the only recourse with the prior art was to remove the in-place fixed-wire dilatation catheter from the patient and advance an over-the-wire/guidewire combination or another fixed-wire catheter. This option however, loses all access to the distal location of the original fixed-wire catheter. The guidewire or the fixed-wire catheter must be steered to the desired intraluminal location. In angioplasty procedures it is not uncommon to find that once the original catheter has been removed it is quite difficult, and sometimes impossible to advance a guidewire or fixed-wire catheter to the original location.